Smaller states are better because they allow the candidates to meet/speak to a larger percentage of the population.
Exactly. California, Florida, Texas, etc as early primary states? Most money wins. Why? Because you are buying air time. In Iowa and New Hampshire- you have to spend time there meeting people and talking to people. More % of people actually interact with the candidates. There is value in that that you simply will never get out of a big state.
Also, I believe that a higher degree of the population takes pride in helping vet candidates and are more involved than your 'normal' voter. You won't get that out of a big state.
You want more diversity? Add a western state like Nevada, Utah or New Mexico- small populations with concentrated population centers. But don't mess with Iowa and New Hampshire. It is just plain dumb to do so if you have EVER whined about money in politics.